I Know What You Did Last Summer by Lois Duncan

It was only an accident -- but it would change their lives forever. Last summer, four terrified friends made a desperate pact to conceal a shocking secret. But some secrets don't stay buried, and someone has learned the truth. Someone bent on revenge. This summer, the horror is only beginning....

Lois Duncan is an acclaimed suspense author for young adults. She has published nearly 50 books for children, including I Know What You Did Last Summer, which was adapted into a highly-successful horror film, and Who Killed My Daughter?, a non-fiction book about the harrowing experience of her daughter's murder.